Cleaning brick checkerwork



Dec. 9, 1952 P. H. CARDW ELL'EI' AL 2,621,136

CLEANING BRICK CHECKERWORK Filed May 25, 1950 O i w I N V EN T 0R3. H Caro we /r0n Oxide fncrus/O/lbnS Pau/ Char/es M L war 3 A TTORNE XS Patented Dec. 9, 1952 UNITED YATES ATENT OFFICE CLEANING BRICK CHECKERWORK ration of Delaware Application May 25, 1950, Serial N0. 164,176

4 Claims.

The invention relates to an improved method of cleaning the working surfaces of brick checkerworks, particularly those used in conjunction with regenerative furnaces, such as open hearth steel furnaces.

The working surfaces of the checkerwork of the regenerator of an open hearth steel furnace become incrusted with iron oxide deposits consisting mainly of particles of Fezoa and F8304 cemented together. These deposits gradually become of considerable thickness, thereby reducing the efficiency of the checkerwork. Heretoiorethe methods of coping with these deposits has been either dismantling the checkerwork and rebuilding it with clean brick or cooling the checkerwork sufficiently to permit entry and manual cleaning by scraping or chipping oil the deposits. In spite of the costliness in time, material, and labor of these methods, no other satisfactory procedures are commercially available for removing these deposits insofar as we are aware.

It is the principal object of the invention to provide a method of removing the iron oxide incrustations from a brick checkerwork which is easily and quickly carried out without the need for dismantling or cooling the checkerwork below operating temperature.

Other objects and advantages will appear as the description of the invention proceeds.

According to the invention, the iron oxide incrustations to be removed are disintegrated and sloughed off by applying to the incrustations while hot, an aqueous solution of one of the carboxylic acids selected from the group consisting of the Water-soluble aliphatic monoand dicarboxylic acids, as by spraying the incrusted checkerwork with the solution.

The invention may be more readily understood from the following detailed description and accompanying drawing diagrammatically illustarting a preferred mode of practicing the invention.

In the drawings, the single figure is a fragmentary isometric view of a checkerwork showing the iron oxide incrustations and an apparatus for carrying out the method of removing therefrom the iron oxide incrustationsaccording to the invention.

Referring to the drawing in detail, there is shown a conventional checkerwork structure I consisting of fire bricks 2 arranged end to end and on edge forming rows, the rows being in crisscrossed tiers forming vertical passages 3 between them. The checkerwork is supported upon the columns 4 and arches 5 forming tunnels 6 communicating with the air passages 3. Walls enclose the checkerwork structure, one of the side walls I and a back wall 8 being partially shown. Rack wall 8 is provided with a series of access openings 9 giving access to the checkerworks.

The apparatus for carrying out the invention includes the tank l0 having a filling opening H and discharge outlet l2. The outlet is connected through valve 13 by pipe I4 to the force pump I5. Attached to the discharge of the pump is a flexible hose it connected to the lance IT. The lance may be made of a straight piece of pipe of suinoient length to reach into the checkerwork through an access opening 9 as indicated. The lance is provided with a spray nozzle 18 at its outer end.

In carrying out the invention employing the apparatus illustrated, an aqueous solution of one of the aforesaid carboxylic acids, e. g. oxalic, citric, acetic, is placed in tank 10 through filling opening I I. By means of the pump l5, the solution withdrawn from the tank is put under pressure and. sprayed onto the incrustations on the checkerwork (while hot) from the nozzle l8 which is inserted into the checkerwork passages through the access holes 9 by means of lance II as shown. It will be apparent that by moving the lance about within the checkerwork passages from each of the access holes in turn treating solution can be sprayed upon all the incrusted surfaces to be cleaned. In spraying the treating solution onto the incrustations, it is desirable to treat the uppermost areas of the checkerwork first, thereby allowing treating solution to trickle downwardly over the incrusted surfaces from top to bottom. The effect of the solution is to disintegrate and slough oif the deposits. These drop onto the floor [9 of the tunnels 6 below the checkerwork forming piles 20 which may be removed in any convenient manner.

The concentration of the carboxylic acid in the solution does not appear to be critical. Concentrations as low as 1 per cent are effective and other concentrations up to saturation at temperatures up to 50 C. or more may be used. A preferable concentration is about 8 per cent.

As already indicated, the checkerwork is to be treated while hot, the preferred temperature being the normal operating temperature of the checkerwork, such as about 2000 F. to 2400 F., although temperatures as low as 1000 F. may be used. It is desirable though not necessary to shut down the checkerwork so as to stop the flow of gases through it while spraying it with the treating solution.

The amount of solvent or cleaning solution of carboxylic acid to use is gauged by observing the results while the solution is sprayed onto the hot checkerwork. Suflicient solution is applied to cause the deposits to be disintegrated and sloughed ofi the checkerwork. The amount of solvent consumed depends upon the thickness of the iron oxide deposits and may vary over wide limits, as for example, from 0.1 to 1.0 gallon per square foot of incrusted checkerwork surface, although other amounts may be used.

The following tabulated observations of the effect of the carboxylic acid solution treatment on a sample of iron oxide incrustation from the checkerwork of an open hearth steel furnace show the disintegrating action of the solution. Each sample is the form of a lump weighing about 5 grams and is heated to 1500 F. and sprayed with the acid solution. The effect of tap water sprayed onto a similar sample heated to 1500" F. is shown for comparison.

The incrusted checkerwork brick heated to operating temperatures and sprayed with sufiicient carboxylic acid treating solution to remove the incrustations shows no ill effects as a result of the acid treatment.

We claim:

1. The method of disintegrating and sloughing off the iron oxide incrustations on the surfaces of a brick checkerwork which comprises spraying onto the incrusted checkerwork surfaces while at a temperature above 1000 F. an aqueous solu tion containing a carboxylic acid selected from the group consisting of the Water-soluble aliphatic monoand dicarboxylic acids in a concentration of at least 1 per cent.

2. The method according to claim 1 in which the carboxylic acid is oxalic and the temperature of the checkerwork is between 1000 F. and 2400" F.

3. The method according to claim 1 in which the carboxylic acid is citric and the temperature of the checkerwork is between 1000 F. and 2400 F.

4. The method according to claim 1 in which the carboxylic acid is acetic and the temperature of the checkerwork is between 1000 F. and 2400" F.

PAUL H. CARDWELL. CHARLES M. LOUCKS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 133,095 Haggett Nov. 19, 1872 865,700 Hernsheim Sept. 10, 1907 1,334,092 Harmeling Mar. 16, 1920 1,428,084 Gravell Sept. 5, 1922 1,954,744 Peterson Apr. 10, 1934 2,013,511 Steinbacher Sept. 3, 1935 

1. THE METHOD OF DISINTEGRATING AND SLOUGHING OFF THE IRON OXIDE INCRUSTATIONS ON THE SURFACES OF A BRICK CHECKERWORK WHICH COMMPRISES SPRAYING ONTO THE INCRUSTED CHEEKERWORK SURFACES WHILE AT A TEMPERATURE ABOVE 1000* F. AN AQUEOUS SOLUTION CONTAINING A CARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF THE WATAER-SOLUBLE ALIPHATIC MONO- AND DICARBOXYLIC ACIDS IN A CONCENTRATION OF AT LEAST 1 PER CENT. 